A bogie for supporting a carbody of a railcar, such as a streetcar, and allowing the railcar to run along a rail is provided under the floor of the carbody. In a common bogie, axles each extending in a vehicle width direction are respectively attached to front and rear portions of a bogie frame so as to be rotatable, and a pair of left and right wheels are attached to each of the axles. The bogie frame is equipped with, for example, air springs configured to absorb vibrations of the carbody. In the railcar, since the carbody on which passengers get is provided on the bogie, the height of a floor surface of the carbody from the ground is high. Therefore, there is a difference in height between an entrance of the carbody and the ground. In recent years, as the streetcars, there are low-floor railcars in which the entrance is provided at a low position to allow elderly people, disabled people, etc. to easily get on and off the railcar from the viewpoint of barrier free.
Here, proposed is a low-floor railcar in which the axles each connecting the left and right wheels are omitted, and the floor of the carbody is lowered by an empty space between left and right independent wheels (see PTL 1, for example). The bogie of this railcar includes: a bogie frame including a pair of left and right side beams and a transom which connects the side beams and is lower in height than the center of the wheel; axle boxes provided on vehicle-width-direction outer sides of the left and right independent wheels; primary suspensions configured to elastically couple the axle boxes to the front portions and rear portions of the side beams, respectively; and secondary suspensions configured to elastically couple front-rear-direction intermediate portions of the side beams to a bottom portion of the carbody. In accordance with the railcar using the above bogie, a carbody passenger room is equipped with a pair of left and right long seats which face each other and sandwich a center aisle located at the center in the vehicle width direction and extending in a front-rear direction, the center aisle can be adequately lowered, and a continuous low-floor portion from the entrance to the center aisle of the passenger room can be formed.